Developing More Sustainable Processes for Plastic Metallization

 
 
 
 
 
 

Developing More Sustainable Processes for Plastic Metallization

The word “sustainable” is widely used now, but what does it mean? What elements of sustainability drive value for users that support innovation investment in the short term?

Often regulation is a major force for change, usually providing clarity around timing and technology, while allowing innovation and investment with an understanding that the market will be open to changes.

In the European Union, REACH (Registration, Evaluation, Authorization and Restriction of Chemical Substances) provides the regulatory framework, giving clear indication of “Substances of Very High Concern” (SVHCs), very early in the process with the creation of the REACH candidate list. Many assume that once a substance is on the candidate list that it will progress towards being restricted or banned following systematic assessments.

However, the process also has political implications where restrictions are not always related to the toxicity, volume or risk of the substance and therefore can be misleading when considering investments in alternative technologies.

Importantly, sustainable initiatives are now being adopted and accelerated beyond regulatory bodies as global awareness of resources and the impact on humans and the environment are voiced and understood by a broader audience. Will the corporate voice, or shareholder concern about sustainability drive changes in process selection faster than the regulators?

Plastic Metallization Solutions

The use of plastics in electronic and industrial component applications continues to grow and diversify due to the benefits in weight, design and performance characteristics when compared to metal alternatives. Functional or decorative metallization of plastic has been a growth industry for more than 50 years, from chrome-plated interior and exterior car parts, to gold- plated aerospace electronic connectors.

Each part has common process elements; etching the plastic for adhesion promotion, catalytic deposition of a conductive seed layer, followed by electrolytic deposition of the functional or decorative layers (including Copper, Nickel, Chromium, Silver, Palladium, Gold and other metals.)

Since the 1960s, the first etching stage typically had used chromic acid, but the toxic chromium trioxide [Cr(VI)] was banned under EU REACH in September 2017. This ban enabled suppliers and users alike to consider investing in innovative and sustainable solutions.

DuPont Interconnect Solutions (ICS), part of the Electronics & Industrial business developed Ecoposit™ CF-800 Chrome-Free Etch, with an initial patent granting in 2013 and initial industrial installation in 2015—both of which were well ahead of the REACH ban deadline.

While many early adopters in the plating community have invested and installed this novel “chrome-free” process technology, regulators have not yet enforced the ban nor have yet confirmed the authorization deadline under which continued use of chromic acid etching will be permitted. This has delayed any substantial industry investment and adoption of the sustainable chrome-free technology.

DuPont Interconnect Solutions recognized this major change as an opportunity to look at the entire metallization process and further invest in innovation in more sustainable products, collectively under the Ecoposit™ Plastic Metallization banner.

The catalytic deposition of a conductive seed layer uses electroless nickel (most common in decorative plastic part metallization) or electroless copper (most common in functional plastic part metallization).

Electroless nickel has been used in ever increasing volume since the 1960s. It includes phosphates, borates and ammonia--all facing increasing restrictions due to their negative impact on humans or the environment, but without substantial regulation preventing its use. DuPont introduced Niposit™ PM-988 Ammonia-Free Nickel providing a robust, industrially proven solution without ammonia and its related use and discharge concerns.

The novel and ground breaking Ecoposit™ XF-1000 Electroless Copper is formaldehyde-free and unlike electroless nickel, does not contain phosphates, borates or ammonia, thus providing a real step forward in sustainable solutions for plastic metallization.

Sustainability is on the Agenda

DuPont Interconnect Solutions has been investing in “green” process chemistry options for many years and continues to develop novel solutions that not only remove substances of concern but deliver cost and performance benefits when compared to existing process solutions.

These include cyanide-free and boric acid-free electrolytes as well as improving coating distribution, improving bath stability, bath life and product yield. All these innovations contribute significantly to the performance, cost and sustainability footprint of the component metallization processes.

For more information, visit https://www.dupont.com/electronic-materials/plating-on-plastics.html